Why do wine “spoil” so quickly after being opened as opposed to hard liquor?

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You can put the cork back in and put it in the fridge, but the flavor is never the same, and sometimes it spoils and tastes unpleasant overnight.

So what makes hard liquor so resilient to time and exposure compared to wine?

In: Chemistry

Wine contains a lot of sugars, and a fairly low alcohol content, which makes it susceptible to bacteria getting in and doing their thing. It also contains a lot of compounds from the grapes that may react poorly with oxygen, or absorb contaminants from the air and produce off flavors.

Distilled spirits generally have a low (or no) sugar content and relatively high alcohol content. This makes them a very hostile environment for microbes. They also tend to not have nearly as many compounds remaining from the original ingredients, as almost everything heavier than water has been stripped by the distilling process.

The organisms that produce alcohol are called yeasts. When yeasts are allowed to consume sugars in an environment that does not contain oxygen, they produce alcohol, and they will do so until they have produced enough alcohol that it kills them. Some yeasts remain though, which is why when beer is bottled, the few remaining yeasts continue to produce gas which causes the beer to be fizzy. Wine is treated before bottling so this does not happen.

Hard liquor is distilled, which means it has been converted to steam and then condensed into liquid again. The concentration of alcohol in liquor is far too high to allow yeast to survive, and most/all are removed during distillation.

When yeasts are allowed to consume sugars in the presence of oxygen, they produce acetic acid instead of alcohol. Acetic acid is what vinegar is made from. Since yeasts can’t survive in concentrated alcohol, they aren’t able to change the alcohol in liquor into acetic acid, but they CAN in wine and beer after it has been opened and oxygen is put in contact with the yeasts.

Others pointed out the wine oxidizes, but they missed the main thing:

There are air-breathing bacteria that can survive a moderate alcohol content, turning the stuff into acetic acid (aka vinegar). The way they used to make vinegar was to just take wine, cider, beer or any other alcoholic beverage, and let it sit in an open vessel, so that bacteria from the environment would infect it and turn acohol into acid.

So when you open a bottle of wine, the exact same thing is going to happen. Oxygen and bacteria get into the bottle, and start producing acetic acid.

Hard liquor doesn’t do that because it has a too high alcohol content for bacteria to live in, although some can survive in a dormant form – alcohol for disinfection has a much higher alcohol content than the usual 40%.

While your question has been answered, nobody has given the 2nd best solution to the problem, a Vacu Vin Wine Saver, which lets you save wine for a long time if necessary. Obviously the best solution is just to drink it all 😉

Obviously these don’t work with sparkling wines, unless you want them flat.